Romulan calendar
- Units
- Ewa (Romulan second) (ENT Novel: The Good That Men Do)
- Siure (Romulan minute) (ENT Novel: The Good That Men Do)
- Dierha (Romulan hour) (ENT Novel: The Good That Men Do)
- Eisae (Romulan day) (ENT Novel: The Good That Men Do)
- Khaidoa (Romulan month) (ENT Novel: The Good That Men Do)
- Fvheisn (Romulan year) (ENT Novel: The Good That Men Do)
- Months
- Tasmeen (ENT Novel: The Good That Men Do)
- At least twenty-one days
- Havreen (ENT Novel: The Good That Men Do)
- At least eight days
- Immediately follows Tasmeen
- K'ri'Brax (ENT Novel: Kobayashi Maru)
- At least 29 days
- After Havreen
- Tasmeen (ENT Novel: The Good That Men Do)
- Correspondences
- Nearly three fvheisn between April 17, 2152 and early February 2155 (ENT Novel: The Good That Men Do)
- Between "Minefield" and chapter 4 of The Good That Men Do
- Tasmeen 5, year unknown > January 24, 2155 (ENT Novel: The Good That Men Do)
- January 30, 2155 > Tasmeen 11, year unknown > February 3, 2155 (ENT Novel: The Good That Men Do)
- Tasmeen 21, year unknown = February 9, 2155 (ENT Novel: The Good That Men Do)
- March 3, 2155 > Havreen 8, year unknown > March 21, 2155 (ENT Novel: The Good That Men Do)
- July 13, 2155 > K'ri'Brax 29, year unknown > July 14, 2155 (ENT Novel: Kobayashi Maru)
- Nearly three fvheisn between April 17, 2152 and early February 2155 (ENT Novel: The Good That Men Do)